Marine structure and method of erecting same



y 1, 1966 w. F. MANNING 3,253,417

MARINE STRUCTURE AND METHOD OF ERECTING SAME Filed March 20, 1963 4 Sheets-Sheet 1 I2 I3 L 40 I 40 IO 22 22 I7 SURFACE WILLIAM F. MANNING INVENTOR.

ATTORNEY ay 31, 1966 w. F. MANNING 3,253,417

MARINE STRUCTURE AND METHOD OF ERECTING SAME Filed March 20, 1963 4 Sheets-Sheet 2 WILLIAM F. MANNING INVENTOR.

BYN

ATTORNEY.

ay 31, 1966 w. F. MANNING 3,253,417

MARINE STRUCTURE AND METHOD OF ERECTING SAME Filed March 20, 1963 4 Sheets-$heet 5 DERRICK BA RGE WATER SURFACE BOTTOM SURFACE BOTTOM WATER SURFACE WILLIAM F. MANNING INVENTOR.

ATTORNEY BY k).

HGJI.

y 1, 1966 w. F. MANNING 3,253,417

MARINE STRUCTURE AND METHOD OF ERECTING SAME Filed March 20, 1963 4 Sheets-Sheet 4 Fflfiofifio 3 50 L 70 Fig 5O WILUAM F. MANNING 22 44 44 22 INVENTOR.

ATTORNEY.

United States Patent 3,253,417 MARINE STRUCTURE AND METHOD 0F ERECTING SAME William F. Manning, Springdale, Conn, assignor to Socony Mobil Oil Company, Inc, a corporation of New York Filed Mar. 20, 1963, Ser. No. 266,658 9 Claims. (Cl. 611-465) This invention relates to a marine structure and a method of erecting same. More particularly, this invention relates to a prefabricated form of-marine drilling structure which may be floated to and erected upon a marine site.

Present-day developments in the oil industry find exploration and production efforts being extended to areas of extremely deep and unprotected water's. For example, the desired objective of obtaining oil production on ocean sites having water depths in excess of 300 feet is not uncommon. The adaptation of conventional shallow water type structures and methods generally is not feasible in waters of such extreme depths. The assembly and installation of the necessary elements comprising presently known fixed type structures present almost unsurmountable problems. Presently employed fioatable barges having extendable legs are not usable at such water depths. While experimentation is now being carried out to develop systems wherein drilling is accomplished without the use of rigid structure between the surface and the ocean bottom, much work remains to be done before such systems may be economically and efficiently utilized. There, therefore, exists a need for apparatus and installation methods for constructing a fixed type, economical drilling structure on the ocean bed of deep waters. It is an object of the present invention to provide apparatus and a method for installing a marine structure on the ocean bed of deep waters. It is another object of the present invention to provide a marine drilling structure supported by the ocean bed and extending to the surface of the water. It isa further object of the invention to provide a permanent or semi-permanent deepwater marine drilling structure which may be prefabricated, floated to a desired marine drilling site, and efficiently and economically erected upon such site. These and further objects of the invention will be evidenced from the following specification taken in conjunction with the accompanying drawings.

In accordance with the invention, there is provided an articulated marine structure which comprises longitudinal, interlockable derrick sections hinged at their base ends to a base assembly in such a manner that the structure may rest in a horizontal, layout position and may be assembled from such position into a derrick type structure supported on a marine bottom. Further, in accordance with the invention, there is provided a method of erecting on a marine site an articulated type structure by floating the structure to the site in a horizontal, layout position, selectively flooding the components of the structure to cause them to sink base end first and fold into assembled condition, and securing the components together to form a derrick supported on the ocean bed.

Referring to the drawings:

FIGURE 1 is a plan View of a marine structure constructed in accordance with one embodiment of the invention in a horizontal, layout position.

FIGURE 2 is a View in elevation illustrating the structure of FIGURE 1 floating at the water surface in a condition for transit to the marine site.-

FIGURE 3 is a fragmentary view in perspective of one section of the structure showing two legs and one of the interlockable brace assemblies.

FIGURE 4 is a view in elevation of the hinge joint 3,253,417 Fatented May 31, 1966 portion of the structure in the encircled area 4 of FIG- URE 2.

FIGURE 5 is a plan view of the hinge structure illus trated in FIGURE 4 and enclosed within the encircled area 5 of FIGURE 1.

FIGURE 6 is a sectional view'of one of the legs of the structure, illustrating in elevation a piling positioned within the leg.

FIGURE 7 is a view in elevation of the structure of an early stage in the erection procedure, together with a diagrammatic representation of a derrick barge employed in the erection procedure.

FIGURE 8 is an elevation view of a more advanced stage in the erection procedure of the structure.

FIGURE 9 is a view in elevation of the structure after its sections have been brought into interlocking relationship and one of the securing pins is being installed.

FIGURE 10 is a view in elevation of the structure in its final position on a marine site with the anchor pilings driven into place in the ocean bed.

FIGURE 11 is a side view in elevation of the structure in the position illustrated in FIGURE 10.

FIGURE 12 is a view in section taken along the line 12- 12 of FIGURE 11.

FIGURE 13 is a view in section taken along the line 1313 of FIGURE 11.

FIGURE 14 is a view, partially in elevation and partially in section, of one of the interlocking joints between the derrick section-s of the structure and shown enclosed within the encircled area 14 of FIGURE 10.

FIGURE 15 is a plan view of the interlocking joint shown in FIGURE 14 and within the encircled area 15 of FIGURE 13.

Referring to the drawings, particularly FIGURE 1, the marine structure ofthe invention is comprised of longitudinal derrick sections 1d and 11, which in the embodiment illustrated may be referred to as derrick halfsections, secure-d at their base ends by means of binge connections to a base and brace assembly 12 in a manner which will permit the entire structure to rest in a layout, horizontal position as illustrated in plan in FIGURE 1 and in elevation in FIGURE 2. Such connecting of the sections of the structure permit its erection by the method illustrated in FIGURES 7 through 11. As will be further described in detail, the derrick sections 10 and 11 are flooded in a controlled fashion to cause the inward folding of the sections into interlocking relationship.

Bottom brace assembly 12 is formed by end braces 13 and side braces 16. Extending diagonally across the base assembly is cross brace 17 which is constructed in two segments secured to a conductor pipe guide 20. Guide 20 is positioned at approximately the geometrical center of the rectangle formed by the base assembly and functions to guide into the ocean bed a string of easing comprising the conductor pipe, not shown, used in the drilling of a well with the structure. Each of the braces 13, 16, and 17 are preferably sections of cylindrical pipe which are sealed to provide buoyancy and prevent the ingress of sea water to the interior of the braces. Each end portion of braces 13 is provided with a bracket 21 adapted to receive a hinge pin for securing derrick sections 10, 11 to the base assembly. The construction of the end portions of braces 13 may best be understood by reference to FIGURE 4.

Derrick sections 10 and 11 are each formed by two legs 22 which have sufficient length to extend from a short distance below the ocean bed to the desired distance above the surface of the water. The diameter of each of the legs is sufiicient both to provide the required structural rigidity for the marine structure and the buoyancy necessary to float the structure in layout position at the waters surface while in transit to the marine site on which the structure is to be erected. If the marine structure is to be used in water 300 feet in depth, the legs 22 may, for example, be 340 to 350 feet in length and have a diameter on the order of about 5 feet. Depending upon the nature of the ocean bed on which the structure is positioned, the base ends of the legs will sink into the bottom a short distance.- Since a drilling platform will be mounted above the water surface on the upper end of the legs, the distance the legs extend above the water surface will be dependent upon the height above the water surface that it is necessary to erect the drilling platform, considering such factors as wind and wave action together with the tides of the sea at the particular site on which the structure is erected.

Each of the legs is constructed of tubular pipe, see FIGURE 6, sealed at opposite ends to provide buoyancy for floating the structure to the marine site. Secured to the base end of each of legs 22 is a solid closure plate 23 which is removed at the marine site to allow flooding of the legs. Closure plates 23 may be secured to the legs by welding them on in a manner which will provide a watertight seal over the base ends of the legs and permit them to be pulled off the legs at the marine site. Connected to each of the closure plates 23 is a cable 24 secured by any convenient means. Cables 24 are utilized to pull the closure plates off the bottoms of the legs in a manner and for a purpose which will be explained hereinafter. Secured to the opposite or upper end of each of legs 22 is another closure plate 25 which is welded or otherwise secured to the legs to provide a watertight seal at the upper end of the legs. Connected to the interior of each of legs 22 through closure plate 25 is an air hose which is employed in a manner to be hereinafter described for controlling the flooding of the interior of each of the legs.

While it is not essential, it is preferred that a piling 31 be initially installed in each of the legs at the time of fabrication of the marine structure in order that the piling will be in place for anchoring of the marine structure when it is in position on a marine site. Piling 31 may be installed and secured within legs 22 by means of a plurality of braces 32 which are welded between the interior of the leg and the exterior of the piling. Several such braces 32 are utilized rather than one complete circumferential brace in order that when flooding of the leg occurs, water may freely flow into the leg around and along the length of the piling. The connection between the leg and the piling need only be secure enough to hold the piling in place during transport of the marine structure and manipulating it into position on the marine bottom. Once the structure is resting in the desired position on the bottom, the pilings are broken loose and driven into the marine bottom to anchor the structure in position. Secured around the interior of the lower portions of the legs and the upper portions of the exterior of the pilings are a plurality of grout lugs 33 which are constructed in the form of circumferential rings and serve to improve the bond between the legs and piling surfaces with cement which is introduced into the leg to provide a means of securing the piling and leg together after the piling has been driven into place in the marine bottom.

Each pair of legs 22 comprising derrick sections 10 and 11 are secured together by means of horizontal braces 40, as illustrated in FIGURES 1 and 3. Each of the legs 22 is secured at its base end by a hinge connection to the base assembly 12, the details of the hinging mechanism being illustrated in FIGURES 4 and 5. A bracket 41 is secured to each of the legs, the bracket in turn being pinned by hinge pin 42 to bracket 21 on an end of end brace 13 of base assembly 12.

Secured along the length of the legs 22 of each of the derrick sections are a plurality of brace assemblies 43 which are positioned at corresponding positions along the length of each pair of legs comprising the derrick sections so that the brace assemblies on one section will be interlockable with the brace assemblies on the other section when the derrick sections are folded into assembled position. Each of the brace assemblies 43 is made up of horizontal brace members 44 connected together by a horizontal brace member 45 and angled brace members 50. The construction of the brace assemblies 43 is best illustrated in FIGURE 3.

When the derrick sections 10 and 11 are folded into interlocking relationship, as illustrated in FIGURES 9- 11, to form the assembled marine structure, it is necessary that the sections be secured together to form a rigid structure. To effect this interlocking of the derrick sections, apparatus comprising a male-female joint between corresponding brace assemblies 43 is provided as illustrated in FIGURES l4 and 15, typical locations of such joints in the completely assembled marine structure being pointed out in the encircled portions 14 of FIGURE 10 and 15 of FIGURE 13, respectively. Secured on the outward end of each of horizontal braces 44 on brace assemblies 43 positioned along the length of derrick section 10 is a male fitting 51 as illustrated in FIGURE 14. Within the outward portion of male fitting 51 is a grout chamber 52 which is provided with holes 53 to allow a securing pin to extend through the grout chamber of the male fitting. Positioned around the male fitting 51 is a seal 54 formed of a material such as rubber. Secured on the outward end of horizontal braces 44 on each of the brace assemblies 43 positioned along the length of derrick section 11 is a female fitting 55 which is adapted in a horizontal direction to receive the male fitting 51 and in a vertical direction to receive a securing pin, as best illustrated in FIGURE 14. Seals are provided within fitting 55 as illustrated to prevent escape of grout along the securing pin. Connected into the upper portion of female fitting 55 is a grout exhaust line 61 which is provided with a specific gravity check valve 62. Exhaust line 61 permits water to be expelled from the joint while it is being filled with grout, and the specific gravity check valve closes at the time the grout flows through the exhaust line to the point of the valve. Each of the male-female joints is maintained in interlocked relationship by locking pin 63. The entire structure is maintained in interlocked relationship, that is, the two derrick sections are maintained interlocked together by means of the use of two locking pins 63, one running down each side of the structure along which the male-female joints of the brace assemblies 43 are located. In other words, one locking pin is inserted from the top of the structure downwardly along one side through all of the male-female joints located on that side, while another pin is similarly inserted down the other side of the marine structure. The seals 54 and 60 in cooperation with the male and female elements, together with the locking pin, provide a sealed condition for each of the male-female joints in order that grout may be introduced into the joints to cement the joints together. Extending the full length of each of the locking pins 63 is a grout channel 64 which may be a small pipe positioned within each pin and communicating with the grout chamber at each level, or each pin itself can be used as a grout channel which communicates with each grout chamber through holes 65 appropriately spaced along the length of each pin. In this event, each pin remains full of grout when the grouting of the joints is complete.

At each of the elevations on the marine structure at which the brace assemblies 43 are positioned, there may be provided conductor pipe guides 70, as illustrated in FIGURE 13, which cooperate with the guide 20 of base assembly 12 for the purpose of guiding downwardly through the structure a conductor pipe employed in drilling a well from the structure. Guides may readily be formed by securing along one of the derrick sections pairs of brace members to the horizontal braces 45 on each of the brace assemblies 43. By thus securing pairs of braces to the brace 45 on each of the assemblies 43 v along one side of one section, such as section 10, of the marine structure, there is provided at each level of the brace assembly, when the sections and 11 are interlocked together a rectangular opening, as illustrated at 70 in FIGURE 13, through which a conductor pipe may be guided downwardly through the marine structure substantially along its longitudinal axis.

The method of assembling or erecting the marine structure of the invention, as diagrammatically illustrated in FIGURES 1, 2, and 710, is carried out in the following manner. Each of the longitudinal derrick sections 10 and 11, together with the base assembly 12, is fabricated in accordance with the above descriptions of these units. It will be readily understood from the above descriptions that each of the derrick sections 10 and 11, including the legs 22, braces 40, and the brace assemblies 43, comprises movable, foldable, unitary structures which are hinged to the base assembly 12 in the manner illustrated in FIGURES 4 and 5. It will readily be recognized that the entire assembly of sections 10 and 11 along with base assembly 12 in its horizontal or layout position, as illustrated in FIGURES 1 and 2, comprises an articulated unit of extreme length, which may, for example, be on the order of 800 or more feet. While such an articuated unit may readily be assembled on an inclined plane and launched much in the manner followed in ship construction, it will be readily recognized that the component units of this assembly, namely, sections 10, 11 and assembly 12, may be fabricated separately and then placed in the water where they are brought together and the hinge connections made.

With the structure floating in the water, as illustrated in FIGURE 2, one end of it is connected by means of a tow line to a tug for transit to the marine site on which the structure is to be erected and anchored. While lines 241 and air hoses 30, which are used in the assembly of the structure at the marine site, may have their ends secured to the towing tug, it is preferred that they be secured in some convenient fashion to the structure itself during transport. Securing the ends of the lines and hoses to the tug presents two major problems. First, due to the extreme length of the structure,'these lines, in order to reach the tug, would have to be several times as long as 'necesary for the erection procedure. Second,

by extending and securing the lines to the tug, they could very easily become entangled. Care should be taken in preparing lines 24 and hoses 3(lfor transport of the structure since the watertight integrity of the structure must be maintained in order for it to float at the surface of the water. To accomplish this, an appropriate fitting should be placed over the ends of hoses 30 to prevent possible flooding of the legs, and lines 24- should be secured to the structure in a manner which will prevent their accidental entanglement and possibly pulling of the plates 23 off of the ends of the legs which would also result in the flooding of the legs. With the structure properly prepared for transport, it is towed by the tug in the same manner as any barge is moved through the ocean.

When the structure has been towed to the marine site on which it is to be erected, with the base assembly portion 12 of the structure being positioned substantially over the location at which the structure is to stand, a der rick barge'TI, as diagrammatically illustrated in FIG- URE 7, is positioned adjacent base assembly 12 and the tow line between the tug and the structure is disengaged. The exact time of disengagement of the tug from the structure will of course depend upon the local problems of maintaining the structure on location during the assembly procedure. In other words, it may be necessary to maintain the tug in engagement with the structure to some extent during the early stages of the assembly procedure to prevent possible drifting of the structure. In order to be properly prepared for the erecting procedure, a number of connections are made between the derrick barge and the structure. Closure lines 72 are connected between the extreme ends of the structure and boom means on the derrick barge. Lines 24 leading from the base end of each of legs 22 are connected to the boom means on the derrick barge. Air hoses 30, one each leading from the outward or upper end of each of legs 22, are connected to valve and air compressor means, not shown, on the derrick barge. While for purposes of simplicity of illustration the derrick barge is shown only in FIGURE 7, with all of the connections made between the barge and the structure, it is to be understood that the derrick barge remains in position with all of the required connections between it and the structure being maintained throughout the procedure of assembling and erecting the structure until the completion of the driving of the pil-ings as illustrated in FIGURES l0 and 11.

With all of the connections between the derrick barge and the structure being made up as illustrated in FIGURE 7, the procedure of actually asembling the structure and securing it to the marine bottom may commence. Closure lines 72 are drawn taut by the boom on the derrick barge, thus exerting forces on the outward ends of sections 10 and 11 tending to urge the outward ends toward each other into folded position. Substantially simultaneously with the drawing taut of lines 72, lines 24 are taken up and pulled with suflicient force, a sudden pulling or jerking possibly being necessary, until the welded seal connect-ion between plates 23 and the lower ends of legs 22- is broken to completely remove the plates from the lower ends of the legs to allow entry of the sea water into the legs to effect flooding of them. FIGURE 7 shows plates.23 pulled from the ends of legs 22. Since controlled flooding of the legs is necessary to properly assemble and erect the structure, it is preferred that closure lines 72 be utilized to lift the outward ends of the derrick sections a short distance, bringing them toward each other to place the sections in a position similar to that illustrated in FIGURE 7 to prevent sudden flooding of the entire legs. If the sea water is allowed to enter the legs with the derrick sections in exactly horizontal position, flooding of the entire legs may occur before control of the flooding can be effected due to failure to trap air in the upper portions of the legs. With the outward ends of the derrick sections lifted up slightly before removal of the plates 23, air will be trapped in the'legs and controlled flooding may be carried out. Once the plates 23 are removed, sea water will begin to enter the base ends of each of the legs, and the extent to which it enters is controlled by the valve and air compressor means on the derrick barge connected to the outward end of the legs through the air hoses 30. Bleeding of the air from the upward or outward ends of the legs to allow entry of more sea-Water into the legs at the base ends is controlled by the valves in hoses 30 on the derrick barge, wh-ile expulsion of the sea water from the base ends of the legs or from any one particular leg may be effected by injecting compressed air through hoses 30. Once the plates 23 are removed from all of the base ends of the legs, flooding into the legs commences and the base ends of derrick sections 10 and 11, together with base assembly 12, begin sinking toward the ocean bed. The rate of descent or sinking of the base ends of the sections and asesmbly 12 is controlled by selective flooding of the legs by manipulation of the air flow through hoses 30. A slow, steady rate of descent is to be preferred. Through the controlled flooding of the legs, the base ends of the structure gradually sink while simultaneously forces are exerted on lines 72, causing the upward and inward folding of the outward ends of the derrick sections. The hinge connections between the base assembly 12 and the derrick sections readily perm-it this folding action. FIGURE 8 represents an intermediate stage in the folding of the derrick sections, the figure showing the appearance of the folding derrick sections at the time they are in a substantially vertical position. The pulling on the closure lines and the selective flooding of the legs of the derrick sections continue until the derrick sections have been completely folded into interlocking relationship with each other, at which time the corresponding brace assemblies 43 on the sections are brought into contact with each other with the male-female joints between the brace assemblies being made up as illustrated in FIGURES 14 and 15. While the bringing of the derrick sections into mated or interlocking relationship may be effected with the base ends of the sections, and thus the legs, resting on the marine bottom, it is to be preferred that the stage of interlocking relationship be reached while the structure is still in a buoyant condition, as illustrated in FIGURE 9.

With the derrick sections 10 and 11 in mated or interlocking relationship, the insertion and securing of -the locking pins 63 to firmly affix all of the male-female joints may be carried out. It will be recalled that two such locking pins 63 are employed with a pin being positioned down each of the two sides along which the malefemale joints are located. In making the insertion of a locking pin 63, the marine structure is brought to an attitude by controlling the flooding in the legs whereby the particular side of the structure in which the pin is being inserted is resting in a vertical position, as illustrated in the dotted-line diagram of FIGURE 9. This may be accomplished by increasing the buoyancy of the legs in the section of the structure along the side opposite that in which the pin is being inserted. The lower end of the pin is placed in the male-female connection of the uppermost set of braces 43 in the structure and the pin driven downwardly to its fullest extent until the lower end of the pin has passed through the lowermost of the malefemale connections. At this point, the portion of the pin resting in the top male-female connection may be welded to the connection and the step of grouting the several male-female connections is initiated. A grout supply line extending from a cement or grout pump on the derrick barge is connected to the upper end of the pin into the grout channel 64, and grout is pumped downwardly through the pin into each of the male-female connections. The grout flows into each of the connections with the water present within the connections being expelled through line 61 and specific gravity check valve 62. The check valve will remain open until all of the water has been expelled from the connections and the connections are filled with the grout. Knowing the approximate volume of the grout-receiving portions of each of the connections and the volume of the grout channel 64 through the pin, together with the pumping rate of the grout pump, it may readily be determined approximately when complete filling of all of the connections has been accomplished. At the completion of the grouting of all of the connections along the first side of the structure, that particular pin is considered secured in position and the grout connection with the derrick barge may be removed. The attitude of the structure is then changed by the previously described controlled flooding of the legs until the other or opposite side of the structure is brought to a vertical position, at which time the second locking pin 63 is inserted and grouted. If desired, the insertion of both pins may be completed and the grouting step is carried through both pins at one time.

With the completion of the securing of both locking pins, all of the legs of the structure are allowed to completely flood, thus causing the sinking of thestructure into a position on the marine bottom whereby the base ends of the legs and the base assembly 12 are resting upon the ocean bed. The derrick barge is then disconnected from the structure. With the structure in completely assembled state and resting on the desired marine site, the plates 25 and air hoses 30 are removed from the upper end of each of the legs and a hammer is inserted into each of the legs into contact with the upper end of pile 31 to drive the pile downwardly into the marine bottom to anchor the structure in place. The force of the hammer will break the spot welds between the braces 32 and the interior of the legs to allow the piling to slide downwardly relatively to the legs into the bottom. With the pilings driven downwardly to the desired extent,

cement or grout is pumped into each of the legs to provide a securing mechanism between each of the legs and its respective piling. The grout lugs on the external surface of the piling and internal surface of the leg serve to improve the bond with the cement and thus achieve a more effective connection between the piling and the leg. With the pilings grouted in place within the legs, a superstructure, not shown, is erected on the upper end of the structure for the purpose of supporting the equipment necessary to drill a well from the structure.

In the event it is preferred, the approach of preinstalling the pilings in the legs may be dispensed with and pilings may be separately transported to the erection site. Such pilings may then be inserted from the surface, driven to the desired depth in the bottom, and welded at their surface ends to the legs. In this latter case, it may not be necessary to grout the pilings to the legs as the welding step will accomplish the securing together of the pilings and legs.

What is claimed is:

1. An articulated marine structure comprising:

(a) two longitudinal derrick half-sections each having a base end and a free end, said derrick half-sections joined at their base ends by hinges to opposite sides of a base assembly to allow said derrick halfsections and said base assembly to be floated in a body of water in an unfolded, horizontal, layout position and to be folded toward each other into interlocking relationship to form a derrick;

(h) each of said derrick half-sections including buoyant hollow legs extending substantially from said base end to the free end thereof, each of said hollow buoyant legs having an opening therein adjacent the base end thereof, said buoyant hollow legs interconnected by cross-bracing members;

(c) bracing assemblies secured to said legs at corresponding positions along the length of each said derrick half-sections, each of said bracing assemblies on one of said derrick half-sections contacting a corresponding bracing assembly on the other of said derrick half-sections when said derrick half-sections are in folded, interlocked relationship;

(d) removable watertight means fixed over said openings in each of said buoyant legs for sealing said buoyant legs while said marine structure is in said unfolded, horizontal, layout position;

(e) erection means secured to said derrick half-sections adjacent to the free ends thereof for drawing said free ends of each of said derrick half-sections up out of the horizontal, layout position;

(f) means operatively connected with the hollow interior of each of said hollow legs for controlling the selective flooding of said hollow legs, after removal of said removable sealing means, and when the free ends of said derrick half-sections have been drawn up out of the unfolded, horizontal, layout position, to cause said derrick half-sections to sink, base ends first, through said water to a marine bottom; and

(g) a pin-receiving aperture formed in each of said bracing assemblies at a position such that said apertures have a common axis when said derrick half-sections are in said interlocking relationship.

2. An articulated marine structure comprising:

(a) a base assembly comprising brace members arranged in rectangular form and having a diagonal brace provided with a conductor pipe guide at substantially its midpoint;

(b) a buoyant hollow leg secured by a hinge connection to each corner of said base assembly;

((1) a plurality of brace assemblies secured in spacedapart relationship at corresponding positions along the length of each of said leg units, each brace assembly on one of said leg units contacting a brace assembly on the other of said leg units when said units are in folded position;

(e) a male fitting on each outward end of each of said brace assemlies on one of said leg units;

(f) a female fitting on each outward end of each of said brace assemblies on the other of said leg units,

said female fittings cooperating with said male fittings to lock contacting brace assemblies together;

(g) said male and female fittings having cooperating means forming sealed chambers within said female fittings adapted to receive grout for cementing said fittings together; 7

(h) plate means secured over the base end of each of said legs to maintain said legs watertight, said plate means being removable to allow flooding of each of said legs during erection of said structure; and

(i) means, secured to the upper end of each of said legs including .a plate and an air hose to form a watertight cover over the upper end of each of said legs during floating transport of said structure and permit air to be bled from and injected into said legs to control the buoyancy of said legs during erection of said structure on an ocean bed.

3. In a method of erecting an articulated marine structure including longitudinal derrick sections hinged adjacent their base ends with respect to each other and having a plurality of lateral brace assemblies at longitudinally spaced intervals along said sections, each of said brace assemblies having a pin-receiving aperture therein, a tubular locking pin long enough to extend simultaneously through the pin-receiving apertures of each of said brace assemblies when said derrick sections interlock, port means in said pin spaced to register with the interiors of each of said pin-receiving apertures, the steps which comprise:

(a) floating said structure in a body of water with said derrick sections in an unfolded, substantially horizontal position;

(b) sinking the base ends of said derrick sections;

(c) simultaneously with step (b) folding said derrick sections toward each other;

(d) bringing said derrick sections into an interlocking relationship with each other by aligning the pin-receiving apertures of said brace assemblies on a common taxis extending through the surface of said water; I

(e) holding said derrick sections together by inserting said tubular locking pin through the aperture of an upper one of said brace assemblies and guiding said pin through the apertures of successively lower brace assemblies until said spaced ports in said pin each registers with the interior of at least one of said apertures; and

(f) injecting grout into each of said apertures through said registered ports from the upper end of said pin to permanently secure said derrick sections together.

4. In the method of claim 3, wherein said derrick sections have buoyancy chambers with means for controlling the buoyancy of said chambers by selective admission and withdrawal of water to and from said chamber, the recited step (b) is accomplished by selectively flooding said buoyancy chambers of said derrick sections to-cause said sections to sink, base ends first, toward the bottom of said body of water.

5. An articulated marine structure comprising:

(a) a base assembly;

(b) derrick half-sections secured by hinge connections to opposite sides of said base assembly and adapted to float in a body of water in an unfolded horizontal position substantially in the plane of said base assembly for transport, and to be folded toward each other as said marine structure is erected ,into a derrick;

(c) a plurality of fittings secured in spaced-apart relationship at corresponding positions along the length of each of said derrick half-sections, fitting on one of said derrick half-sections interengaging loosely with a fitting on the other of said derrick half-sections to form cooperating pairs of fittings when the derrick half-sections are in the folded position, said pairs of fittings on the opposing derrick half-sections consisting of a male fitting on one derrick half-section and a female fitting on the other derrick half-section, said male fitting interengaging with said female fitting in a substantially linear path;

(d) a chamber formed within each of said pairs of interengaged male and female fittings by an annular space between the interior of said female fitting and the exterior of said male fitting, aligned pin-receiving passages in said male and female fittings forming a composite pin-receiving passage extending through said chamber normal to the path of said interengagement whereby the extending of a tubular pin through said pin-receiving passage substantially seals said chamber so that grout can be injected into said chamber through said tubular pin, and with ports therein registering with the interior of said chamber, for cementing together said pair of fittings.

6. An articulated marine structure as recited in claim 5 wherein a number of said composite pin-receiving passages through said pairs of interengaging fittings are aligned in a common axis whereby an elongated tubular pin can be extended through the aligned pin-receiving passages for the simultaneous grouting of said chambers. 7. An articulated marine structure as recited in claim 5 wherein seal means are fixed to one fitting of each pair of interengaging fittings to coact with the interior of said female fitting and the exterior of said hollow male fitting whereby an open end of said chamber at the open end of said female fitting is sealed, seal means mounted within the ends of said aligned passage extending through said female fitting of said pair of interengaged fittings whereby the chamber is completely sealed when a tubular pin extends through the pin-receiving passage and coacts with said sealing means therewithin. 8. An articulated marine structure as recited in claim 5 wherein said male fitting is hollow whereby said port means in said tubular pin extended through said tubular pin-receiving passage connects with the hollow interior of said male fitting so that grout injected through said tubular pin will enter the interengaged pair of fittings through said hollow male fitting.

9. An articulated marine structure 'as recited in claim 5 wherein each of said derrick half-sections includes an integral hollow buoyant chamber extending substantially the length of said derrick half-section, and having a first opening adjacent the base assembly and a second opening adjacent the upper end of said derrick halfsections, plate means secured over said first opening in each of said integral buoyant chambers to maintain said chamber watertight, said plate means being removable to allow flooding of said buoyant chamber during erection of said structure; and a means secured over said second opening in each of said buoyant chambers including a sealing means and an air hose extending therethrough to form a watertight cover over said second opening in each of said buoyant chambers during floating transport of said structure and to permit air to be bled from and injected into said buoy-ant chamber to control the buoy- References Cited by the Examiner UNITED STATES PATENTS 2,221,067 11/1940 Wilson 189-16 2,581,098 1/1952 Guenzel 61465 2,608,829 9/1952 Knapp 51-46.5 2,637,172 9/1952 Howard 6146.5

CHARLES 5/1956 Butts 189-36 6/1956 Kuss et a1. 61-46.5 12/1956 Harris 6146 10/1958 Swiger et a1 6146.5 1/1961 Mangone 6146.5 4/1961 Crake 6146 E. OCONNELL, Primary Examiner.

1o JACOB SHAPIRO, EARL J. WITMER, Examiners. 

1. AN ARTICULATED MARINE STRUCTURE COMPRISING: (A) TWO LONGITUDINAL DERRICK HALF-SECTIONS EACH HAVING A BASE END AND A FREE END, SAD DERRICK HALF-SECTIONS JOINED AT THEIR BASE ENDS BY HINGES TO OPPOSITE SIDES OF A BASE ASSEMBLY TO ALLOW SAID DERRICK HALFSECTIONS AND SAID BASE ASSEMBLY TO BE FLOATED IN A BODY OF WATER IN AN UNFOLDED, HORIZONTAL, LAYOUT POSITION AND TO BE FOLDED TOWARD EACH OTHER INTO INTERLOCKING RELATIONSHIP TO FORM A DERRICK; (B) EACH OF SAID DERRICK HALF-SECTIONS INCLUDING BUOYANT HOLLOW LEGS EXTENDING SUBSTANTIALLY FROM SAID BASE END TO THE FREE END THEREOF, EACH OF SAID HOLLOW BUOYANT LEGS HAVING AN OPENING THEREIN ADJACENT THE BASE END THEREOF, SAID BUOYANT HOLLOW LEGS INTERCONNECTED BY CROSS-BRACING MEMBERS; (C) BRACING ASSEMBLIES SECURED TO SAID LEGS AT CORRESPONDING POSITIONS ALONG THE LENGTH OF EACH SAID DERRICK HALF-SECTIONS, EACH OF SAID BRACING ASSEMBLIES ON ONE OF SAID DERRICK HALF-SECTIONS CONTACTING A CORRESPONDING BRACING ASSEMBLY ON THE OTHER OF SAID DERRICK HALF-SECTIONS WHEN SAID DERRICK HALF-SECTIONS ARE IN FOLDED, INTERLOCKED RELATIONSHIP; (D) REMOVABLE WATERTIGHT MEANS FIXED OVER SAID OPENINGS IN EACH OF SAID BUOYANT LEGS FOR SEALING SAID BUOYANT LEGS WHILE SAID MARINE STRUCTURE IS IN SAID UNFOLDED, HORIZONTAL, LAYOUT POSITION; (E) ERECTION MEANS SECURED TO SAID DERRICK HALF-SECTIONS ADJACENT TO THE FREE ENDS THEREOF FOR DRAWING SAID FREE ENDS OF EACH OF SAID DERRICK HALF-SECTIONS UP OUT OF THE HORIZONTAL, LAYOUT POSITION; (F) MEANS OPERATIVELY CONNECTED WITH THE HOLLOW INTERIOR OF EACH OF SAID HOLLOW LEGS FOR CONTROLLING THE SELECTIVE FLOODING OF SAID HOLLOW LEGS, AFTER REMOVAL OF SAID REMOVABLE SEALING MEANS, AND WHEN THE FREE ENDS OF SAID DERRICK HALF-SECTIONS HAVE BEEN DRAWN UP OUT OF THE UNFOLDED, HORIZONTAL, LAYOUT POSITION, TO CAUSE SAID DERRICK HALF-SECTIONS TO SINK, BASE ENDS FIRST, THROUGH SAID WATRER TO A MARINE BOTTOM; AND (G) A PIN-RECEIVING APERTURE FORMED IN EACH OF SAID BRACING ASSEMBLIES AT A POSITION SUCH THAT SAID APERTURES HAVE A COMMON AXIS WHEN SAID DERRICK HALF-SECTIONS ARE IN SAID INTERLOCKING RELATIONSHIP. 